In order to reduce the dependence on foreign oil, various types of wave power generation apparatuses have been proposed to harness wave energy. However, these apparatuses have been economically unsuccessful. Wave power produces low-speed, high forces, and the motion of these forces is not in a single direction. However, most readily available electric generators operate at a higher rate of rotations per minute (RPM). Furthermore, a successful wave power generation apparatus must be able to operate reliably in a harsh environment such as in corrosive saltwater and under less than optimal conditions for example in storms, under constant wave action, etc. It is therefore an objective of the present invention to provide an apparatus based on a power converting method of changing reciprocating motion from wave energy into rotational motion for rotating a rotor of a rotary generator. An exemplary method for achieving this in the present invention functions similarly to a conventional pull starter or a retractable measuring tape. Examples of prior art wave power generation apparatuses related to the present invention are disclosed below.
Some known apparatuses use a cable that serves as both a power transmitting cable for a reel and a mooring cable for mooring a float that primarily captures ocean wave energy. However, a returning spring for rewinding the cable may be damaged when excessive external forces by big wave is exerted thereon. When deploying this type of apparatus, large ocean space is required to prevent the cable from being tangled, leading to an increase in the deployment cost over a period of time.
Known apparatuses use various different methods for converting wave energy and storing the converted energy. Some known apparatuses use only one rotational direction for converting wave energy and a flywheel for storing rotational energy. Other known apparatuses use both rotational directions without a flywheel, and yet other apparatuses use both rotational directions and a flywheel, which is the most efficient method due to the maximization of the total input energy to the generator. However, in these advanced apparatuses, the volume and weight of the apparatuses and the number of parts are increased.
Some known apparatuses use a compact generator assembly. However, since these apparatuses only use either the roll or pitch motion of wave energy, power output is less than a conventional coal or oil powered power plant.
Some known apparatuses use a float that includes a linear generator. However, the moment of inertia is not converted into electrical energy in these apparatuses and only one linear generator can be disposed on one axle that guides the movement of the float.
In wave power generation apparatuses, conventional sealing for rotating parts requires continuous maintenance, which increases operating cost over a given period of time. Other apparatuses use a rigid structure for guiding the movement of a float; however, the rigid characteristics of the structure increases stress on the structure due to the continuous ocean wave motion.
In view of the foregoing, there is a need for improved techniques for providing a wave power generation apparatus for harnessing wave energy that is able to survive storm damage and saltwater corrosion, and can be readily maintained, replaced, deployed, operated, endured and economically manufactured while keeping its high level of efficiency. There is an urgent need for a wave power generation apparatus that satisfies those criteria, and can generate reliable useful energy from wave energy.
Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.